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Find Minimum in Rotated Sorted Array

Problem​

Suppose an array of length n sorted in ascending order is rotated between 1 and n times. For example, the array nums = [0,1,2,4,5,6,7] might become:

  • [4,5,6,7,0,1,2] if it was rotated 4 times.
  • [0,1,2,4,5,6,7] if it was rotated 7 times.

Notice that rotating an array [a[0], a[1], a[2], ..., a[n-1]] 1 time results in the array [a[n-1], a[0], a[1], a[2], ..., a[n-2]].

Given the sorted rotated array nums of unique elements, return the minimum element of this array.

You must write an algorithm that runs in O(log n) time.

Solution Approach​

Expected Time Complexity: O(n)O(n)

Click - to see solution code
class Solution {
   public:
    int findMin(vector<int>& nums) {
        int start = 0, end = nums.size() - 1;
        while (start < end) {
            int mid = (start + end) / 2;
            if (nums[mid] >= nums[start] && nums[end] < nums[mid]) {
                start = mid + 1;
            } else {
                end = mid;
            }
        }
        return nums[start];
    }
};